Semiconductor fabrication processes are typically conducted with the substrates supported within a chamber under controlled conditions. Some of the important controlled conditions include, but are not limited to, fluid flow rate into the reaction chamber, temperature of the reaction chamber, temperature of the fluid flowing into the reaction chamber, and temperature of the fluid throughout the fluid line.
Fluid lines are generally used to convey an applicable fluid from a source container or other supply apparatus to the reaction space for processing. The fluid line may carry a liquid, gaseous, or even solid containing solution material depending on the application. Further, the size, shape, and arrangement of the fluid lines may be custom designed based on precursor demands and space constraints within the semiconductor fabrication facility.
In order to obtain a consistent reaction environment, maintaining the correct flow rate of precursor at a correct temperature are among the key factors. However, the importance of maintaining the temperature of the precursors at a uniform temperature is not limited to just the reaction chamber. A number of precursors have a limited temperature range of gaseous phase composition. Thus, in order to maintain the correct flow rate, the precursor must be maintained within a slim temperature range from the source container, through the fluid line, and finally into the reaction chamber.
A number of heater jackets have been developed in an attempt to maintain consistent fluid temperatures during the transition from the temperature controlled source container to the reaction chamber. One common example is cloth heater jackets which surround the fluid line and include a cloth inner layer in contact with the fluid line. The cloth heater jacket may be generally flexible, but is difficult to position on fluid lines with bends. Further, if a heating element is also included, the heating element is generally in contact with or close to the fluid line and a thermocouple may inadvertently read higher or lower temperatures because the heating element is contacting the same surface as the thermocouple. Still further, since the heater jacket is in direct contact with the fluid line, there may be additional wear and tear on the inner surface of the heater jacket from the contact with the fluid line, particularly around bends in the fluid line or at microfittings.
An alternative to heater jackets includes heat tape, which is inexpensive but time consuming to install. Further, when a section of the fluid line needs to be worked on or replaced, the heat tape must be removed, scraped, and a new section installed in its place.